The chair of the banking inquiry is writing to the main financial institutions putting them on notice that they may be required to give evidence to the body.
The all-party group is due to begin public hearings next month.
Chairman Ciarán Lynch is contacting the main financial institutions in the State, including Government departments, the Central Bank and the commercial banks.
He is also to write to IMF boss Christine Lagarde, the European Central Bank and other international bodies to establish lines of communication with a view to calling witnesses to appear before the inquiry.
The European Central Bank, which played a central part in Ireland's bailout, has yet to decide whether its officials will appear.
This preliminary contact is being established in the expectation that the Committee on Procedure and Privileges will soon give the formal green light to the banking inquiry.
The main public hearings will begin next year.
However, next month Mr Lynch's committee expects to call the authors of a number of reports on the banking crash to give evidence in hearings aimed at setting the context for its main investigation.
In the meantime, the committee is continuing its work behind the scenes.
It has appointed UCD Professor of Economics Karl Whelan in conjunction with business advisory group FTI Consulting to provide expert support for the context phase of the inquiry.
